2.2.0.25falsefalse0611 - Disclosure - Property, Plant and Equipment (Details)truefalseIn Millions, unless otherwise specifiedfalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) USD ($) / shares $Jan-01-2011_Mar-31-2011http://www.sec.gov/CIK0000065984duration2011-01-01T00:00:002011-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$3true0etr_PropertyPlantAndEquipmentTextualsAbstractetrfalsenadurationProperty Plant and equipment.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringProperty Plant and equipment.falsefalseProperty Plant and Equipment (Textuals) [Abstract]4false0etr_NetCarryingValueOfPlantetrfalsedebitinstantNet carrying value of plant.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse420000000420falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNet carrying value of plant.No authoritative reference available.falsefalseNet carrying value of plant5false0us-gaap_ConstructionPayableCurrentus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse131300000131.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCarrying value as of the balance sheet date of obligations incurred and payable for the acquisition of merchandise, materials, supplies and services pertaining to construction projects such as a housing development or factory expansion not classified as trade payables. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Subparagraph a -Article 5 falsefalseConstruction expenditures included in accounts payable6false0etr_AdditionalRenewalPeriodOfLicenseetrfalsenadurationAdditional renewal period of license.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2020falsefalsefalsefalsefalseOtherxbrli:integerItemTypeintegerAdditional renewal period of license.No authoritative reference available.falsefalseAdditional Renewal Period Of License7false0us-gaap_ImpairmentOfLongLivedAssetsHeldForUseus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse00falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 26 -Subparagraph b Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 7, 25 falsefalseImpairement of Vermont Yankee15Property, Plant and Equipment (Details) (USD $)MillionsUnKnownUnKnownUnKnowntruetrue